[BOJ] 2580번 스도쿠

#include < iostream>
using namespace std;

int board[9][9];

bool c[9][10];
bool c2[9][10];
bool c3[9][10];

int square(int i,int j){
    return (i/3)*3+(j/3);
}

int n;

void go(int z){
    if(z==81){
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                cout<<board[i][j]<<" ";
            }
            cout<<endl;
        }
        exit(0);
    }

    int x = z/n;
    int y = z%n;

    if(board[x][y] !=0){
        go(z+1);
    }else{
        for(int i =1;i<10;i++){
            if(c[x][i] == false && c2[y][i] == false && c3[square(x,y)][i] == false){
                c[x][i] = c2[y][i] = c3[square(x,y)][i] = true;
                board[x][y] = i;
                go(z+1);
                c[x][i] = c2[y][i] = c3[square(x,y)][i] = false;
                board[x][y] = 0;
            }
        }
    }

}

int main(){
    n =9;
    for(int i=0;i<9;i++){
        for(int j=0;j<9;j++){
            cin>>board[i][j];

            if(board[i][j] != 0){
                c[i][board[i][j]] = true;
                c2[j][board[i][j]] = true;
                c3[square(i,j)][board[i][j]] = true;
            }
        }
    }

    go(0);

    return 0;
}

https://www.acmicpc.net/problem/2580

2580번: 스도쿠